Blackboard.



B LAC K B 0A R D (Application led Apr. 4, 189B.)

2 Sheets-Sheet l,

(No Model.)

w. J. sEMELRoTH.

BLACKBOARD.

\App1ication led Apr. 4, 1898.) (No Model.) 2 Sheets-Sheet 2.

UNITED STATES PATENT FrIcEe WILLIAM J. SEMELROTH, OF ST. LOUIS, MISSOURI, ASSIGNOR OF ONF-THIRD TO W'ILLIAM H. .HERRIOIL OF SAME PLACE. I

BLACKBOARD.

SPECIFICATION forming part of Letters Patent No. 634,149, dated October 3, 1899. Application filed April 4, 1898. Serial No. 676,427. (No model To all whom, t may concern.'

Be it known that I, WILLIAM J. SEMELEOTH, a citizen of the United States, residing at St.Y Louis, State of Missouri, have invented certain new and useful Improvements in Blackboards, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to certain new and useful improvements in blackboards of the ilexible style in which the writing-surface is furnished by a properly-prepared canvas or web adapted to be rolled up for transportation.

The main object of my improvements is to provide simplicity and compactness of construction and to adjust the tension on the web, whereby it may be conveniently used without a rigid back or support, thus maintaining the desirable yielding touch for the chalk in use.

To this end my improvements have reference to a box adapted to form the top and base support for the rollers or end sticks of the web forming the blackboard-surface, have reference to a skeleton frame of special construction for supporting said web top and base, have reference to means for adjusting one of said web-supports with regard to the other, have reference to adjusting one of said Web-rollers in its support, have reference to a receptacle for chalk and eraser, and have reference to other points of detail hereinafter described and claimed;

In the accompanying drawings, on which like reference-letters indicate corresponding parts, Figure l represents a perspective view of my device pack-ed for transportation; Fig. 2, a view with the cover removed and a portion of the contents in section to show arrangement for packing.; Fig. 3, a perspective view of a socket-piece for the legs adapted to form a receptacle for the eraser and chalk; Figs. 3 and 3P, an eraser and chalk adapted to lit within such socket-piece Fig. 4, an edge View of my device set up on a portable frame; Fig. 5, a face view ofy the same; Fig. 6, an enlarged cross-section on the line x a; of Fig. 2,.

showing an inside end view of the base and cap; Fig. 7, a plan view of the same on g/ y; Fig. 8, a detail sectional view of the adjustment of the base and leg, and Fig. 9 a back view of the base.

The letter A designates a web with prepared blackboard or silicate surface, preferably in the form of an endless band, and mounted on rollers or end sticks B B at the base and top, respectively. The web may be otherwise than double, if desired. The rollers constitute simple supporting-sticks for the web. The preferable form,however,is double, as shown, on account of the large amount of surface provided. These rollers are supported rotatably in the base O and cap O, which are adapted to form the packing-case for the device When dismembered for transportation. The ends of the cap and base are formed with intermatching portions and a common opening c, in which a screw-threaded pin D or other device secures the cap and base together when used as a casing.

One of the supports, the base preferably, is provided with a slot E at each end, in which is mounted the journal of the supporting roller, as indicatedin Figs. 5 and 6. A screwthreaded opening F opposite one end of the slot is adapted to receive the screw-pin D, which will bear upon the journal of the roller and force it down in the slot F., as shown in Figs. 5 and 6. The opposite roller, B' for instance, is provided with journ'als that engage in a U-shaped bearing at one or both ends carried by the cap O.

The framework is in the form of a skeleton spider consisting of front legs G G and rear leg I-I, adapted to fit in a socket-piece I to form a three-legged support. Branching arms J J, also mounted in the socket-piece, engage the cap O by any suitable means, such as a lipand-dowel arrangement, as shown in Fig. 4. It will be seen that the socket-piece is substantially at the center of the framework and that the arms .I .I form angles with the legs G G and H, whereby the pressure of the chalk upon the Web is carried down to the door in three directions; also, the socket-piece is set back of the web to avoid contact therewith, and the tension on the web itself assists in binding the legs and arms in their sockets.

The base C is adjustably mounted on thel legs G by any suitable arrangement, preferably that shown in Figs. 8 and f), consisting l of a T-head projection K from the leg adapted to engage with a vertical slot Lin the back of the base. 'lhe end of the slot is enlarged to receive the head K and the base will slide down upon the projecting head, as shown in Fig. El. The screw-pin D' through the bottom of the base engages the head K and draws the base downward to firm adjustment. Finer adjustment of the ends of the rollers themselves is provided by the screw-pins D upon the journals themselves, as thc edges of the web are inclined to stretch and cause a slackness which it is my aim to overcome by the several means of adjustlnent shown. Either or both forms of adjustment may be used, according to circumstances. The tension thus secured is sufficient fo provide a yielding, spring-like, or cushion surface without other lateral support behind the web. Practical use has demonstrated that the absence of a rigid backing or a writing-surface that is itself rigid renders the use ot' my blackboard much less tiresome to the hand of the operator and admits of finer gradations of shading and writing effects. By varying the tension on the web any degree of lateral cushion effect may be produced, as the operator may desire.

Referring to Fig. 2, it will be seen that the legs are substantially the length of the casing, one leg fitting within the folds of the web. The two arms with the socket-piece make up the length, as shown, the width of the socketpiece being equal substantially to the width of the two arms. The folds of the web also provide a space for a pointer M, the handle of which is preferably hollow to provide a place for storing chalk.

I have provided a special form of hollow socket-piece having the top and bottom perforated to form the sockets for the legs and arms, but the interior forming a receptacle for the eraser 3 when packed in the case and also space for the chalk 3b, as indicated in the figures. Thus the outfit is complete and all the spaces are utilized, preventing rattling and shaking of the parts within the case and reducing the size of the same to a minimum.

Referring again to Figs. it and 5, it will be seen that the triangular arrangement of the legs provide two points of resistance to pressure upon either arm J J. This promotes rigidity of the framework and the steadiness of its foothold. Other adjusting devices for the ends of the rollers may be used and other means for fastening the base adjustably to the legs or the cap to lthe top of the arms may be employed without diverging from my main object of securing adjustment of tension upon the web, as hereinbefore described. I therefore do not limit myself to the exact forms illustrated, which are shown as constituting one arrangement and construction for carrying out my invention.

It will be seen from Figs. 4 and 5 that the two members of the packing-case thus divided along diagonally opposite longitudinal edges and mounted on a suitable framework, so as to be turned toward each other, constitute a cap for the upper roller and a shelf at the lower roller for the deposit of chalk erased from the web and a convenient rest for the eraser when not in use. It is also desirable to adjust the upper roller and its cap upon the arms J J, so that it may be kept level. This I accomplish by a thulnb-screw d, preferably mounted in the cap C' and bearing against the end of the arm J, so as to raise the cap more 01 less, which maybe done Without disengaging it from the dowel-and-lip connection of the arm. Any warping or irregular inclination of the arms J or the legs may thus be corrected through the adjustment of the cap and the base-supports for the rollers. Another function of the adjustments of the cap and base is the effect they have upon the tension of the web; but itwill be seen that these two adjustments and the adjustment of the ends of the rollers within the base all cooperate in effecting the proper tension and mounting of the web.

While I have described a special form of framework for supporting rollers or end sticks for the prepared web-surface, I do not confine my invention to such portable framework or any special support, whether temporary or permanent, and may employ anyor all of the adjustments hereinbefore described for adjusting the position of the web and securing variation of tension upon the same; also, while the web-surface is preferably double, as shown in the figures, to afford increased blackboard surface I may employ but a single web and fold or otherwise bind one or both of the ends over the rollers, as indicated by dotted lines, Fig. 4, which rollers will thus form end sticks and may or may not be rotatable.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is

l. The combination with a flexible web and end sticks or rollers supporting said web at the top and bottom, of a cap and a base for said sticks or rollers respectively, a framework adapted to support said cap and base, and screw adjustments for varying the located position of said cap and base on said framework.

2. A portable blackboard comprisin ga flexible prepared web, rollers for said web, top and base supports for said rollers adapted to form a packing-case, a skeleton framework consisting of a central socket-piece, diverging legs below, and arms above said piece of lesser length than said roller-supports,whereby they can be packed within said case, means for securing said top and base supports to said framework, and means for adjusting the tension of said web.

` 3. A portable blackboard comprising a prepared web, top and bot-tom rollers for said web, a top and a base in which said rollers are respectively mounted, and each consisting of two sides of a casing for packing the IOO IIO

dismembered blackboard, a framework consistin g of a central socket-piece and divergin g arms and legs above and below said socketpiece, the top support being mounted on said arms, an adjustable fastening for the basesupport and said legs, consisting of a socket in one member, and a projection from the other member adapted to interlock, and a screw-pin to effect the adjustment of said projection in said slot, substantially as described.

4. A portable blackboard comprising a skeleton framework consisting of a central socketpiece having perforations in the top and bottom, diverging arms and legs of substantially equal length, adapted to be mounted in said perforations and constitute a spider-framework, a prepared web and supports therefor adapted to be mounted adjustably on said framework, and to be packed in with said web when dismembered for transportation.

5. A portable blackboard comprising a packing-case divisible longitudinally along diagonally opposite edges, provided with bearings to form two roller-supports when mounted on the framework, the base forming a shelf for chalk and eraser, in Combination with a prepared web, rollers adapted to be mounted in said supports and carrying said p packing-case when mounted on said framework, and means to fasten said case when packed and secure the contents thereof.

In testimony whereof I affix my signature in presence of two witnesses.

WILLIAM J. SEMELR'IH.

Witnesses:

ALFRED A. MATHEY, H. M. PLAISTED. 

